How to create a payment gateway?

Check the bill’s hospital/healthcare MCC or purpose code and confirm the hospital is NPCI-verified for high-value UPI.

Validate the payable amount against the applicable per-transaction and daily caps before showing eligibility.

Confirm via the gateway/PSP pre-auth response that the high-limit category is accepted.

Show a higher-limit eligible banner only after all checks pass and log the validation for audit.

Use a purpose-code mapper that assigns the correct automotive/vehicle MCC based on the product (car, bike, commercial vehicle).

Embed this purpose code in the UPI collect/debit payload so the gateway logs it correctly.

Store the purpose code + UPI txn ID in the reconciliation ledger for audit and settlement matching.

Block UPI initiation if a down payment lacks a mapped purpose code

Use purpose-code/MCC-driven GL mapping so vehicle down-payment UPI receipts post to the correct vehicle sales, deposit/escrow, tax and fee ledgers.

Add split-settlement rules to allocate down payment across dealer settlement, taxes, dealer commissions, and platform fees with parent→child UPI txn links.

Enforce NPCI/bank per-txn (₹5L) and daily (₹10L) cap checks before posting and flag over-limit receipts for manual review or auto-split.

Persist immutable UPI txn ID, purpose code, merchant verification flag, and parent/child links on every ledger entry to support reconciliation, refunds and audits.

Integrate the ERP finance module with the PSP/NPCI UPI limit-eligibility API and tag each payment as EVENT_TICKETING before the check.

If the API returns higher-limit support for the customer’s bank, show a banner like Your bank supports higher UPI limits for ticket purchases,  up to ₹X available.

Cache eligibility results per bank for a few hours and fall back to standard-limit messaging when no enhanced limit is returned.

Maintain a category→limit table for UTILITY_PAYMENTS (per-txn + daily caps) and tag each payment with that category before intent creation.

Pre-validate: reject or auto-split if amount > perTxnLimit and check (today_inflow_for_category + amount) ≤ dailyAggregateLimit per VPA/merchant.

Call PSP/NPCI eligibility APIs for bank-specific overrides when available, then record RRNs and update daily counters after settlement for audit and reconciliation.